The present invention relates, in general, to an electric machine, and more particularly to a fan housing for accommodating an electric machine with external fan.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
Many technical applications require an auxiliary ventilation of an electric machine. A typical example involves a servomotor constructed as permanent magnet synchronous motor for operating machine tools. The arrangement of an auxiliary fan results in a more powerful operation of the motor. Typically, externally ventilated motors are surrounded by a metal jacket so that cooing air is routed in a gap between the metal jacket and the motor housing to provide an effective cooling action. Such a construction is shown by way of example in FIG. 1. A servomotor 1 is enveloped by a metal jacket 2 which is pushed from the rear, i.e. output-distal motor side, upon the servomotor 1. Adjustable rubber pads are used to clamp the metal jacket to the motor housing. Attachment of the servomotor 1 to a motor-driven element such as a machine tool (not shown) is realized by inserting screw fasteners through bores 3 provided at an end face of the servomotor 1. The provision of the metal jacket 2 renders however this assembly difficult as access to the screw heads of the screw fasteners is obstructed. As a result, the assembly is time-consuming and relatively complicated.
It would therefore be desirable and advantageous to provide an improved electric machine with auxiliary ventilation to obviate prior art shortcomings.